More than anything else, the phenotype of an organism determines how it interacts with the environment. It’s subject to natural selection, and may help to unravel the underlying evolutionary processes. So shape traits are key elements in many ecological and biological studies.
Commonly, basic parameters like distances, areas, angles, or derived ratios are used to describe and compare the shapes of organisms. These parameters usually work well in organisms with a regular body plan. The shape of irregular organisms – such as many plants, fungi, sponges or corals – is mainly determined by environmental factors and often lacks the distinct landmarks needed for traditional morphometric methods. The application of these methods is problematic and shapes are more often categorised than actually measured.
As scientists though, we favour independent statistical analyses, and there’s an urgent need for reliable shape characterisation based on numerical approaches. So, scientists often determine complexity parameters such as surface/volume ratios, rugosity, or the level of branching. However, these parameters all share the same drawback: they are delineated to a univariate number, taking information from one or few spatial scales and because of this essential information is lost. Continue reading →
Many animals rely on movement to find prey and avoid predators. Movement is also an essential component of the territorial displays of lizards, comprising tail, limb, head and whole-body movements.
For the first time, digital animation has been used as a research tool to examine how the effectiveness of a lizard’s territorial display varies across ecological environments and conditions. The new research was published today in the journal Methods in Ecology and Evolution.
The BES Microbial Ecology Special Interest Group is running a workshop today (Thursday 2 November) on Novel Tools for Microbial Ecology. To compliment this workshop, Xavier Harrison has edited a Virtual Issue of the best Methods in Ecology and Evolution articles on advances in methods of studying microbial evolution and ecology from the past few years.
Advances in Next-Generation Sequencing (NGS) technology now allow us to study associations between hosts and their microbial communities in unprecedented detail. However, studies investigating host-microbe interactions in the field of ecology and evolution are dominated by 16S and ITS amplicon sequencing. While amplicon sequencing is a useful tool for describing microbial community composition, it is limited in its ability to quantify the function(s) performed by members of those communities. Characterising function is vital to understanding how microbes and their hosts interact, and consequently whether those interactions are adaptive for, or detrimental to, the host. The articles in this Virtual Issue cover a broad suite of approaches that allow us to study host-microbe and microbe-microbe interactions in novel ways.
How do we know how many fish there are in the ocean? 1000, 1 billion, 1000 billion? We can’t catch them all and count – that’s not practical. Nor can we make observations from Earth-orbiting satellites – light does not penetrate far into the ocean. What we can use is sound.
Sound travels well in water (faster and further than it does in air), so we can use scientific SONAR (echosounders) to produce sound waves and record backscatter from organisms and communities. This provides information concerning their biomass, distribution and behaviour. A recent study used echoes from the mesopelagic zone (200 – 1,000m) to predict global mesopelagic fish biomass to be between 11 and 15 billion tonnes (that’s a lot), suggesting that mesopelagic fish communities could potentially provide global food security.
10 mesopelagic classes are shown for the open-ocean, echo intensity (a proxy for biomass) increases from blue to red. Coastal zones excluded. Longhurst provinces overlaid. Shapefile here. Proud et al. (2017)
The comparative methods we use to study the evolution of traits are mainly based on the idea that since species share a common evolutionary history, the traits observed on these lineages will share this same history. In the light of phylogenetics, we can always make a good bet about how a species will look if we know how closely related it is to another species or group. Comparative models aim to quantify the likelihood of our bet being right and use the same principle to estimate how fast evolutionary changes accumulate over time. Continue reading →
Measurements of morphological features are important for ecological studies, especially on free-ranging wild animal species. Conventionally, specimens either dead or in captivity are used for morphometric studies, which is difficult in the case of wild species for several reasons.‘In situ measurements of animal morphological features: a non-invasive method’ presents a new way to estimate an individual’s morphometric measurements using metadata from digital photographs.
Dr. Mylswamy Mahendiran and Mr. Mylswamy Parthiban, two of the authors of the article, discuss their paper in the video below. The authors cover the main messages of the article – including who will benefit from reading it; how their method is relevant to animal welfare and wildlife studies; the scope and utility of digital photographic advancements; and how other disciplines could use this method.
A salamander having its skin swabbed to test for Bsal infection.
Imagine you’re at the doctor’s office. You’re waiting to hear back on a critical test result. With recent emerging infectious diseases in human populations, you are worried you may be infected after a sampling trip to a remote field site. The doctor walks in. You sit nervously, sensing a slight tremble in your left leg. The doctor confidently declares, “Well, your tests results came back negative.” In that moment, you let out a sigh of relief, the kind you feel throughout your body. Then, thoughts start flooding your mind. You wonder– what are the rates of false negatives associated with the test? How sensitive is the diagnostic test to low levels of infection? The doctor didn’t sample all of your blood, so how can they be sure I’m not infected? Is the doctor’s conclusion right?
Now, let’s say I’m the doctor and my patient is an amphibian. I don’t have an office where the amphibian can come in and listen to me explain the diagnosis or the progression of disease − BUT I do regularly test amphibians in the wild for a fatal fungal pathogen, known as Batrachochytrium dendrobatidis (commonly known as Bd). Diseases like Bd are among the leading causes of the approximately one-third of amphibian species that are threatened, near threatened, or vulnerable to extinction. To test for Bd, and the recently emerged sister taxonBatrachochytrium salamandrivorans (hereafter referred to as: Bsal), disease ecologists rely on non-invasive skin swabs. Continue reading →
Sea otters (Enhydra lutris) are an apex predator of the nearshore marine ecosystem – the narrow band between terrestrial and oceanic habitat. During the commercial maritime fur trade in the 18th and 19th centuries, sea otters were nearly hunted to extinction across their range in the North Pacific Ocean. By 1911, only a handful of small isolated populations remained.
But sea otter populations have recovered in many areas due to a few changes. The International Fur Seal Treaty in 1911 and the Marine Mammal Protection Act (1972) protected sea otters from most human harvest. Wildlife agencies helped sea otter colonisation by transferring them to unoccupied areas. Eventually, sea otters began to increase in abundance and distribution, and they made their way to Glacier Bay, a tidewater glacier fjord and National Park in southeastern Alaska. Continue reading →
Understanding how animals perceive, learn and remember stimuli is critical for understanding both how cognition is shaped by natural selection, and how ecological factors impact behaviour.Unfortunately, the limited number of protocols currently available for studying insect cognition has restricted research to a few commercially available bee species, in almost exclusively laboratory settings.
In a new video Felicity Muth describes a simple method she developed with Trenton Cooper, Rene Bonilla and Anne Leonard for testing both lab- and wild-caught bees for their preferences, learning and memory. They hope this method will be useful for students and researchers who have not worked on cognition in bees before. The video includes a tutorial for carrying out the method and describes the data presented in their Methods in Ecology and Evolutionarticle, also titled ‘A novel protocol for studying bee cognition in the wild‘.
Protecting wildlife calls for a profound understanding of species’ habitat demands to guide concrete conservation actions. Quantifying the relationships between species and their environment using species distribution models (SDMs) has attracted tremendous attention over the past two decades. Usually these species-environment relationships are estimated on coarse spatial scales, using globally-interpolated long-term climate data sets. While they’re useful for studies on large-scale species distributions, these environmental predictors have limited applications for conservation management.
Climatic data were the first environmental information available with global coverage, but a wide range of Earth observation techniques have increased the availability of much finer environmental information. This allows us to quantify species-environment relationships in unprecedented detail. We can now shift the scale that SDMs operate at, resulting in more useful applications in conservation – SDMs now enter the matrix.
This shift in scale brings new challenges, especially for species using multiple distinct habitat types to survive. The landscape matrix, which has been negligible at the broad (global) scale, is hugely important at the fine (local) scale. It is not only that we need to quantify certain habitat types but also need to consider their arrangement in the landscape, which is basically what the landscape matrix is about. But as we enter the matrix, things become difficult. Continue reading →